The webinar led by Lauren Stewart of BookNet Canada focuses on standards and certification in the book industry, particularly discussing the transition from ONIX 2.1 to ONIX 3.0, and the upcoming ONIX 3.1. Key topics include the importance of adhering to metadata standards and the challenges that arise during this transition, including the deprecation of certain data elements. Tom Richardson, the speaker, emphasizes the need for collaboration among data senders and retailers to improve metadata quality and facilitate smoother transitions between standard versions.